Flax Seed Nutrition
Yes, flax seed is high in most of the B vitamins, magnesium, and manganese, but this little seed is just getting started. There are three additional nutrient groups which flax seed has in abundance, and each has many benefits.
Flax seed is Rich in Omega-3 Fatty Acids: Omega-3 fatty acids are a key force against inflammation in our bodies. Mounting evidence shows that inflammation plays a part in many chronic diseases including heart disease, arthritis, asthma, diabetes, and even some cancers. This inflammation is enhanced by having too little Omega-3 intake (such as in fish, flax, and walnuts), especially in relation to Omega-6 fatty acid intake (in such oils as soy and corn oil). In the quest to equalize the ratio of these two kinds of oils, flax seed can be a real help.
Most of the oil in flax seeds is alpha linolenic acid (ALA). ALA is an Omega-3 which is a precursor to the fatty acids found in salmon and other fatty cold-water fish (called EPA and DHA). Because not everyone is able to easily convert ALA into EPA and (especially) DHA, it is best not to rely solely on flax for your Omega-3 intake, but ALA also has good effects of its own, and definitely helps in the Omega 3/6 balance.
Flax Seed is High in Fiber: You’d be hard-pressed to find a food higher in fiber -- both soluble and insoluble -- than flax. This fiber is probably mainly responsible for the cholesterol-lowering effects of flax. Fiber in the diet also helps stabilize blood sugar, and, of course, promotes proper functioning of the intestines.
Phytochemicals: Flax seed is high in phytochemicals, including many antioxidants. It is perhaps our best source of lignans, which convert in our intestines to substances which tend to balance female hormones. There is evidence that lignans may promote fertility, reduce peri-menopausal symptoms, and possibly help prevent breast cancer. In addition, lignans may help prevent Type 2 diabetes.
Note that a) flax seeds need to be ground to make the nutrients available (otherwise they just “pass through”) and b) flax seed oil alone contains neither the fiber nor the phytochemicals of whole flax seed meal.
Flax Seed Safety and Side Effects
Concerns about flax seed revolve around four potential issues. However, remember that a lot of research about the wonders of flax show little or no problems from eating it –- to the contrary, it has shown many benefits.
Big Fiber Load: Since flax has such a high fiber content, it's best to start with a small amount and increase slowly, otherwise cramping and a "laxative effect" can result. People with irritable bowel syndrome may have an especially strong reaction to it, and should be extra-careful. More about fiber, including tips to prevent problems.
Oxidation/Rancidity: The oil in flax is highly unsaturated. This means that it is very prone to oxidation (rancidity) unless it is stored correctly. The very best way is nature’s own storage system – within the seed. Flax seeds not exposed to large amounts of heat stay safe to eat for at least a year. However, flax meal, and especially flax oil, are a different story. The meal, stored away from heat and light, will keep fresh for a few months, and the oil must be protected by refrigeration in dark containers, preferably being consumed within a few weeks of opening.
Actually, the surprising thing about flax is not that the oils go rancid, but that they don’t go rancid as quickly as we would think, considering how unsaturated they are. The oils are quite stable when the seeds are used in baked foods, for example. Researchers theorize that this is due to the high levels of antioxidants in the seeds.
Hormonal Effects: Lignans contain phytoestrogens. Although research has shown them to be beneficial so far, it is unknown what effect high doses of phytoestrogens might have.
Cyanide: Like many other foods (cashews, some beans, and others), flax contains very small amounts of cyanide compounds, especially when consumed raw. Heat, especially on dry flax seeds, breaks these compounds down. However, our bodies have a capacity to neutralize a certain amount of these compounds, and the US government agencies say that 2 tablespoons of flaxseed (~3 T of flax meal) is certainly safe and is probably an “effective dose” for health purposes. Various researchers who have used up to 6 daily tablespoons of the seed in different studies indicate that the amount they were using was safe.